Scalp Edited Slides by Rama Abbady Dr. Heba Kalbouneh Associate - PDF document

Scalp Edited Slides by Rama Abbady Dr. Heba Kalbouneh Associate Professor of Anatomy andHistology

• It is the soft tissue that covers the skull cap Scalp • Extension: Front: supercilliary arch Frontal bone Scalp is the hairy area of the head; سأرلا ةورف Back: superior nuchal line Occipital bone Sides: zygomatic arch Zygomatic + temporal bone Highest point of the scalp is called Vertex Dr . Heba Kalbouneh

To assist one in memorizing the names of the five layers of the scalp, use each letter of the word SCALP to denote the layer of thescalp S - S kin Cutaneous Membrane C - C onnective tissue (subcutanous tissue) A - A poneurosis Tendon of the inserted muscle Space filled with L - L oose connective tissue P - P ericranium (periosteum) Periosteum of the cranial bones Skull Dr . Heba Kalbouneh -Inside the skull is the cranial cavity which contains the brain -The brain is surrounded by 3 layers of connective tissue called meninges, the outermost layer is called dura mater.

The SCALP consists of five layers: S- Skin C-Connective tissue (dense) A-Aponeurotic layer L-Loose connective tissue P-Pericranium The first three of which are intimately bound together and move as a unit They move on the periosteum of the cranial bones Dr . Heba Kalbouneh

S - S kin C - Connective tissue A -Aponeurosis Fleshy part of a muscle, white rich is collagen type 1 L - Loose connective tissue Space filled with loose connective tissue P - Periosteum . Heba Kalbouneh Dr

1- Skin  Rich in hair follicles, sebaceous glands and eccrine sweat glands The sebaceous gland secrete the oily material into the hair canal to lubricate the hair and the skin Blockage of the ducts of the sebaceous gland or the hair canal Sweat Sebaceous with the oily material results in sebaceous cysts gland gland Scalp is a common site for sebaceous cysts . Heba Kalbouneh Dr -Accumulation of the oily material

2- Connective tissue Made of fibrous septa which unite the skin to the underlying aponeurosis Contains numerous blood vessels, nerves, and fat -Also because of the fibrous septa Thus wounds of the scalp bleed profusely but heal very rapidly B It is often difficult to stop the bleeding of a scalp wound A The blood vessels do not retract and close when lacerated because the connective tissue in which they are found holds them open . Heba Kalbouneh Local pressure applied to the scalp is the A: Aponeurosis only satisfactory method of stopping the B: Space filled with loose connective tissue bleeding Dr Diploic vein: drains the diploe of the bone

Fibrous septa 1- Unite the skin to the underlying aponeurosis of the occipitofrontalis muscle 2- Divide the connective tissue layer into small compartments 3- Hold the cut blood vessels open (in case of scalp wound) . Heba Kalbouneh • When a blood vessel is lacerated, the normal physiological response is : contraction, retraction and blood clot formation, BUT the fibrous septa here holds the cut blood vessel open  that ’ s why Dr the wound of the scalp bleed profusely • In order to stop bleeding, local pressure must be applied • Infection in this layer of the scalp is localized due to the fibrous septa

Emissary veins Emissary vein: connects an extracranial vein with an intracranial vein within the cranial cavity but outside the brain Emissary veins : are devoid of valves , connects the veins of the scalp (2 nd layer) with the intracranial venous sinuses 1- Equalize the pressure between intracranial and extracranial veins 2- Selective cooling of the head !!!!!!! Serve as routes where infections are carried into the cranial cavity from Intracranial venous sinus the extracranial veins to the intracranial veins. Emissary veins connect the veins outside the cranium to the venous sinuses inside the cranium Dr . Heba Kalbouneh This vein penetrates the connective tissue, aponeurosis, loose connective tissue, cranial bones and the intercanial cavity

Under the subcutaneous tissue there is dense type of fat that is not affected by obesity Dr . Heba Kalbouneh

3- Epicranial aponeurosis ( Galea aponeurotica) Consists of the occipitofrontalis muscle Occipitofrontalis has a frontal belly anteriorly and an occipital belly posteriorly and an aponeurotic tendon connecting the two The lateral margins of the aponeurosis are attached to the . Heba Kalbouneh temporal fascia Dr

Muscles of the Scalp Occipitofrontalis Origin: Frontal belly: skin of the eyebrows Occipital belly: highest nuchal line/ superior nuchal line Insertion: Epicranial aponeurosis Nerve supply: Facial nerve (temporal and posterior auricular All the muscles of facial expression are supplied by branches) the facial nerve Action: Moves scalp on skull The frontal bellies of the occipitofrontalis raises the eyebrows in expressions of surprise or horror (wrinkling of forehead). Dr . Heba Kalbouneh Contraction of muscles attached to the skin moves the skin producing facial expressions

Frontalis muscle & Galea aponeurotica Contraction of this muscle produces transverse wrinkles Dr . Heba Kalbouneh

The tension of the epicranial aponeurosis, produced by the tone of the occipitofrontalis muscles, is important in all deep wounds of the scalp. The aponeurosis connects the frontalis and occipitalis muscles. If it is cut coronally. contraction of the muscle usually gapes the wound For satisfactory healing to take place, the opening in the aponeurosis must be closed with sutures Dr . Heba Kalbouneh Laterally, the aponeurosis of this muscle is attached to the superior temporal line

Styloid process of the temporal bone Mastoid process Dr . Heba Kalbouneh Course of facial nerve: -It leaves the cranial cavity by passing through two processes: styloid process & mastoid process -The facial nerve emerges from the cranial cavity from the stylomastoid foramen

The stylomastoid foramen In the interval between the styloid and mastoid processes Dr . Heba Kalbouneh

Dr . Heba Kalbouneh Temporal nerve Facial Nerve As the facial nerve runs forward within the substance of the parotid salivary gland it divides into its five terminal branches: Motor branches 1-The temporal 2-The zygomatic 3-The buccal (Cheek) Posterior auricular nerve 4 The mandibular 5 The cervical Parotid gland Facial nerve -Before entering the parotid gland, the facial nerve gives a branch that runs posterior to the auricle called posterior auricular nerve which supplies the occipital belly -The frontal belly is supplied by the temporal branch

(Spaced filled with loose connective tissue) 4- Loose areolar tissue The subaponeurotic space is the potential space beneath the epicranial aponeurosis and is filled with loose areolar tissue Remember the attachment of Epicranial aponeurosis layer!!! Frontalis muscle has no bony attachment Blow on the skull Hemorrhage in the 4 th layer of the Blood accumulates in this layer spreads scalp may cause raccoon eye over the entire extent of the aponeurosis reaching the eyelid and presents as a black eye Dr . Heba Kalbouneh -Since the 4 th layer of the scalp is a space, infection in this layer is diffused not localized -Bleeding in the 4 th layer of the scalp will diffuse in the space, but this diffusion is limited posteriorly and laterally but not anteriorly -Posteriorly: the occipital belly is attached to the superior nuchal lines -Laterally: the aponeurosis is attached to the superior temporal line -Anteriorly: no bony attachment, so the blood passes and fills the upper and lower eyelids

The subaponeurotic space contains emissary veins This layer is called the dangerous area of the scalp Infections in the subaponeurotic space can spread to intracranial venous sinuses through emissary veins (valveless) Infection spreads by the emissary veins (valveless) to the skull bones, causing osteomyelitis of the flat bone through the dipolic vein. Dipolic vein: drains the diploe of the flat bone Emissary vein . Heba Kalbouneh Dipolic vein Intracranial venous sinus Dr

5-Pericranium Fibrous membrane  Is the periosteum covering the outer surface of the skull bones.  Removable, except in the area of sutures  The periosteum on the outer surface of the bones becomes continuous with the periosteum on the inner surface of the skull bones at the sutures . THEREFORE if there is any fluid collection beneath the pericranium (Cephalhaematoma/ subperiosteal hematoma) it will take the shape of the related bone . Heba Kalbouneh Dr -Bleeding under the periosteum takes the shape of the underlying bone (Subperiosteal hematoma/ Cephalhaematoma) -Happens to the newborn because of the use of certain tools during delivery, which may cause bleeding of one of the periosteal vessels

Nerve supply of the scalp 10 sets of nerves on each side of the scalp 5 in front the auricle 5 behind the auricle 4 sensory 4 sensory 1 motor 1 motor Nerves in front the auricle Nerves behind the auricle 1 Supratrochlear nerve 1- Great auricular nerve (ant rami C2 C3) 2 Supraorbital nerve 2- Lesser occipital nerve (ant rami C2 ) 3 Zygomaticotemporal nerve 3- Greater occipital nerve (post rami C2 ) 4 Auriculotemporal nerve 4- Third occipital nerve (post rami C3 ) 5 Temporal branch of facial nerve 5- Posterior auricular branch of facial nerve supplying the frontal belly of supplying the occipital belly of occipitofrontalis occipitofrontalis -Sensory nerves behind the auricle only the lesser Dr . Heba Kalbouneh occipital and the greater occipital nerves are required